From 33ce1fe80567ac71a945cfc119ffc4ea8b1e9b4f Mon Sep 17 00:00:00 2001
From: Ian Gulliver <flamingcow@gmail.com>
Date: Sat, 20 Jun 2015 05:45:26 +0000
Subject: [PATCH] More resilient method for determining when we've reconnected.

---
 clients/c/cosmopolite-int.h |  1 +
 clients/c/cosmopolite.c     | 15 ++++++++++-----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/clients/c/cosmopolite-int.h b/clients/c/cosmopolite-int.h
index b7dbc58..95b3be5 100644
--- a/clients/c/cosmopolite-int.h
+++ b/clients/c/cosmopolite-int.h
@@ -13,6 +13,7 @@ struct cosmo {
   pthread_cond_t cond;
   bool shutdown;
   char *profile;
+  char *generation;
   json_t *command_queue;
   json_t *ack;
   json_t *subscriptions;
diff --git a/clients/c/cosmopolite.c b/clients/c/cosmopolite.c
index e210727..1dfcb6f 100644
--- a/clients/c/cosmopolite.c
+++ b/clients/c/cosmopolite.c
@@ -307,12 +307,15 @@ static json_t *cosmo_send_rpc(cosmo *instance, json_t *commands, json_t *ack) {
   }
 
   json_t *poll_response = json_array_get(command_responses, 0);
-  int new_poll;
-  if (json_unpack(poll_response, "{sb}", "new", &new_poll)) {
+  const char *instance_generation;
+  if (json_unpack(poll_response, "{ss}", "instance_generation", &instance_generation)) {
     fprintf(stderr, "invalid poll response\n");
   } else {
-    if (new_poll) {
-      assert(!pthread_mutex_lock(&instance->lock));
+    assert(!pthread_mutex_lock(&instance->lock));
+    if (!instance->generation || strcmp(instance_generation, instance->generation)) {
+      free(instance->generation);
+      instance->generation = strdup(instance_generation);
+
       size_t i;
       json_t *subscription;
       json_array_foreach(instance->subscriptions, i, subscription) {
@@ -342,8 +345,8 @@ static json_t *cosmo_send_rpc(cosmo *instance, json_t *commands, json_t *ack) {
 
         cosmo_send_command_locked(instance, cosmo_command("subscribe", arguments));
       }
-      assert(!pthread_mutex_unlock(&instance->lock));
     }
+    assert(!pthread_mutex_unlock(&instance->lock));
   }
 
   json_t *to_retry = json_array();
@@ -575,6 +578,7 @@ cosmo *cosmo_create(const char *base_url, const char *client_id, const cosmo_cal
 
   instance->shutdown = false;
   instance->profile = NULL;
+  instance->generation = NULL;
   instance->command_queue = json_array();
   assert(instance->command_queue);
   instance->ack = json_array();
@@ -605,6 +609,7 @@ void cosmo_shutdown(cosmo *instance) {
   json_decref(instance->ack);
   json_decref(instance->subscriptions);
   free(instance->profile);
+  free(instance->generation);
   curl_easy_cleanup(instance->curl);
 
   free(instance);